scholarly journals Improvements in Topical Ocular Drug Delivery Systems: Hydrogels and Contact Lenses

2015 ◽  
Vol 18 (5) ◽  
pp. 683 ◽  
Author(s):  
Andreza Maria Ribeiro ◽  
Ana Figueiras ◽  
Francisco Veiga

Conventional ophthalmic systems present very low corneal systemic bioavailability due to the nasolacrimal drainage and the difficulty to deliver the drug in the posterior segment of ocular tissue. For these reasons, recent advances have focused on the development of new ophthalmic drug delivery systems. This review provides an insight into the various constraints associated with ocular drug delivery, summarizes recent findings in soft contact lenses (SCL) and the applications of novel pharmaceutical systems for ocular drug delivery. Among the new therapeutic approaches in ophthalmology, SCL are novel continuous-delivery systems, providing high and sustained levels of drugs to the cornea. The tendency of research in ophthalmic drug delivery systems development are directed towards a combination of several technologies (bio-inspired and molecular imprinting techniques) and materials (cyclodextrins, surfactants, specific monomers). There is a tendency to develop systems which not only prolong the contact time of the vehicle at the ocular surface, but also at the same time slow down the clearance of the drug. Different materials can be applied during the development of contact lenses and can be combined with natural inspired strategies of drug immobilization and release, providing successful tools for ocular drug delivery systems. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

2014 ◽  
Vol 679 ◽  
pp. 118-127 ◽  
Author(s):  
Deirdre M. McElroy ◽  
Luke M. Geever ◽  
Clement L. Higginbotham ◽  
Sinead M. Devery

Hydrogel soft contact lenses have been investigated as delivery systems for ophthalmic drug products in response to the need for more efficient ophthalmic drug delivery systems. Ocular drugs delivered via eye drops have a low residence time in the eye resulting in as low as 5% bioavailability of the therapeutic agent. This study investigates the effect of varying concentrations of the photoinitiator diphenyl (2,4,6-trimethylbenzoyl)-phosphine oxide (TPO) on the physicochemical properties of hydrogel soft contact lenses for ophthalmic drug delivery purposes. Contact lens samples were synthesised via photopolymerisation with a range of initiator concentration. Gel fraction and swelling results indicated that increasing the photoinitiator concentration increased the efficiency of the gel network and reduced the water content of contact lens samples. Fourier transform infra-red spectroscopy (FTIR) analysis was employed to confirm polymerisation of the lenses and also indicated the presence of residual photoinitiator in lenses with higher TPO concentrations.


2010 ◽  
Vol 51 (11) ◽  
pp. 5403 ◽  
Author(s):  
Henry F. Edelhauser ◽  
Cheryl L. Rowe-Rendleman ◽  
Michael R. Robinson ◽  
Daniel G. Dawson ◽  
Gerald J. Chader ◽  
...  

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaohong Hu ◽  
Lingyun Hao ◽  
Huaiqing Wang ◽  
Xiaoli Yang ◽  
Guojun Zhang ◽  
...  

Soft contact lenses can improve the bioavailability and prolong the residence time of drugs and, therefore, are ideal drug carriers for ophthalmic drug delivery. Hydrogels are the leading materials of soft contact lenses because of their biocompatibility and transparent characteristic. In order to increase the amount of load drug and to control their release at the expected intervals, many strategies are developed to modify the conventional contact lens as well as the novel hydrogel contact lenses that include (i) polymeric hydrogels with controlled hydrophilic/hydrophobic copolymer ratio; (ii) hydrogels for inclusion of drugs in a colloidal structure dispersed in the contact lenses; (iii) ligand-containing hydrogels; (iv) molecularly imprinted polymeric hydrogels; (v) hydrogel with the surface containing multilayer structure for drugs loading and releasing. The advantages and disadvantages of these strategies in modifying or designing hydrogel contact lenses for extended ophthalmic drug delivery are analyzed in this paper.


Author(s):  
MRINMOY DEKA ◽  
ABDUL BAQUEE AHMED ◽  
JASHOBIR CHAKRABORTY

Eye is a sensitive organ and is easily injured and infected. Delivery of drugs into eye is complicated due to removal mechanism of precorneal area results decrease in therapeutic response. Conventional ocular delivery systems like solution, suspension, ointment shows some disadvantages such as rapid corneal elimination, repeated instillation of drug and short duration of action. In situ polymeric delivery system will help to achieve optimal concentration of drug at the target site, thereby helps to achieve the desired therapeutic concentration. There are various novel ocular drug delivery systems such as In-situ gel, dendrimers, niosomes, nanoparticulate system, collagen shield, ocular iontophoresis suspension and ocusert etc. In situ gelling systems are liquid upon instillation and undergo a phase transition to form gel due to some stimuli responses such as temperature modulation, change in pH and presence of ions. Various attempts have been made towards the development of stable sustained release in-situ gels. Newer research in ophthalmic drug delivery systems is directed towards an incorporation of several drug delivery technologies, that includes to build up systems which is not only extend the contact time of the vehicle at the ocular surface, but which at the same time slow down the removal of the drug. This is a review based on ocular in situ gels, characteristization, techniques and evaluation of in situ ophthalmic drug delivery systems,


2018 ◽  
Vol 11 (1) ◽  
pp. 380
Author(s):  
Harsha Vardhani Kondepati ◽  
Girish Pai Kulyadi ◽  
Vamshi Krishna Tippavajhala

2020 ◽  
Vol 11 (44) ◽  
pp. 6988-7008 ◽  
Author(s):  
Duc Dung Nguyen ◽  
Jui-Yang Lai

Recent exploitations of stimuli-responsive polymers as ophthalmic drug delivery systems for the treatment of eye diseases are summarized and discussed.


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